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Cannot use send later when Outlook DLP add-in for Mac is installed


Article ID: 225027


Updated On:


Data Loss Prevention Endpoint Prevent Data Loss Prevention


You have deployed the DLP Add-in for Outlook on the Mac OS via the Microsoft Admin Center for Office 365

Since then you've noticed that some functionality in Outlook is impaired for example:

  • The Send button is disabled when Outlook is in offline mode
  • The 'Send Later' option is not available




Release : 15.7, 15.8

Component : Outlook Add-in for Mac OS


There are some known limitations to the OnSend Addin types, generally. Please note the points below.


  • The Outlook Addin is required for DLP detection on Mac OS 11.x or greater
  • Windows machines do not need this add-in, they use a COM add-in for Outlook which is applied during agent installation


The majority of the limitations below apply to all 'On-Send' type of add-ins in Outlook, not just the Symantec DLP one.

  • It only works for Office 365 subscription.
  • Send Later feature is not available with onSend add-ins
  • Only one ItemSend event is supported per add-in.
  • OnSend Add-in is not available for group mailboxes.
  • OnSend Add-ins cannot be published to AppSource.
  • OnSend Add-ins does support Outlook in Offline mode
  • OnSend requires API requirement set 1.8 of Office Javascript. So, Outlook for Mac version 16.30+ which supports it.
  • OnSend does not work with mail marked 'Do Not Forward' and 'Encrypt Only' options
  • OnSend does not work with AIP Encrypted Emails generated by selecting below Encrypt options:
    • Confidential \ All Employees
    • Highly Confidential \ All Employees

See Microsoft article (external) for additional details